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Challenges in storing a record soybean crop

By Staff | Oct 19, 2018

The Oct. 11 USDA Crop Production report forecasts Iowa farmers to harvest a record 606 million bushels of soybeans and an average yield of 61 bushels per acre.

Many grain elevators and a few farms were already carrying over more old-crop soybeans than normal. USDA reported that U.S. soybean stocks on Sept. 1 stood at 438 million bushels, up 45 percent from a year ago. Come Sept. 1, 2019, U.S. soybean stocks are forecast to increase to 885 million bushels, which if realized would be a new record.

Iowa farms will likely be storing large amounts of soybeans both on-farm and commercially this next year amid a record harvest and an ongoing trade dispute with China. Many farmers plan to use older, smaller grain bins to store their soybeans. Storing soybeans can come with its own set of challenges, especially with the cool, wet harvest conditions. Consider that some of these soybeans might be stored for more than one year.

Soybean storage tips

As with all grains, spoilage and reduced germination will occur quickly if storage moisture is too high. The high oil content of soybeans makes them even more susceptible to spoilage than corn; therefore, soybeans need to be about two points dryer than corn for proper storage. In a normal year, natural, unheated air will dry soybeans to 13 percent moisture. But in cool, wet, fall conditions, supplemental heat may be required.

Soybeans with less than 15 percent moisture can be dried with bin fans. Soybean seed stored over one planting season should be 12 percent moisture or less, while carryover seed should be stored at 10 percent moisture or less.

Iowa State University (ISU) Extension and Outreach specialists encourage farmers to be careful when drying soybeans. Compared to corn, soybeans are fragile and can be damaged by air that is too hot or too dry and can be damaged from rough handling.

Soybeans have about 25 percent less airflow resistance than shelled corn, so fans sized for corn drying will produce greater airflow through soybeans. Greater airflow means faster drying. Consider reducing heat for soybeans by limiting air drying to 130 -140 degrees Fahrenheit (F) for commercial beans and 100 -110 degrees F for seed beans.

Low temperature drying

Low-temperature dryers should have a full perforated floor and a fan that can push an airflow of one to two cfm/bu. up through the grain. To avoid over-drying and cracking of soybeans, size heaters on low-temperature bins for no more than 20 degree F temperature rise and use an in-plenum humidistat to shut off the heater when the relative humidity of the drying air is below 45 percent.

Drying time depends on air flow, weather, and initial moisture content but will probably be 3 -6 weeks. Check the soybean moisture and condition every day. Resume drying in the spring if necessary. If you detect mold, heating, or foul odors during drying, unload the bin and sell, or dry the soybeans at high temperatures.

Other strategies for storing soybeans:

– Level off your bins immediately after harvest.

– Avoid using worn augers and mechanical spreaders that will damage the seed while filling.

– Aerate your bin as soon as it is filled to remove the heat, regardless of the moisture.

– Aerate the stored soybeans to maintain grain temperature at 35? – 40?F in winter and 40? – 60?F in summer.

– Check your bin every couple of weeks throughout the season for crusting, aerate if needed.

– Be sure your bin is ready for unloading before winter.

For more information on soybean storage tips, search the ISU Extension and Outreach Integrated Crop Management website.

crops.extension.iastate.edu/soybean-storage-tips

Steve Johnson is an Iowa State University Extension and Outreach farm management specialist. He can be reached at sdjohns@iastate.edu.

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